Gasoline composition containing nu-aminoalkyl-substituted 2-aminoalkane detergents



United States Patent 3,388,979 GASOLINE COOSITION CONTAINING N- AMINOALKYL-SUBSTITUTED 2 AMINQ- ALKANE DETERGENTS George J. Kautsky, El 'Cerrito, Calif., assignor to Chevron Research Company, a corporation of Delaware N0 Drawing. Filed June 8, 1964, Ser. No. 373,514 Claims. (CI. 44-69) ABSTRACT OF THE DISCLOSURE Leaded gasoline composition containing N-aminoalkylsubstituted Z-aminoalkanes in which the alkane is straight chain and contains from about 9 to 24 carbon atoms.

This invention relates to gasoline compositions for spark ignition internal combustion engines. More particularly, the invention concerns gasoline compositions containing new detergent additives which substantially reduce carburetor deposits in spark ignition internal combustion engines.

In the operation of spark ignition internal combustion engines there have been problems of rough idling and engine stalling, and carburetor adjustments and reconditioning are often necessary to provide satisfactory service. It is found, particularly in the case of stop-and-go driving in metropolitan areas, that such stalling and idling problems are more frequent, especially in the case of multithroat carburetors of the type employed in many presentday automobiles. It has been determined that the rough idling and engine stalling are primarily due to the accumulation of deposits in the throttle body section of the carburetors. As the deposits build up, the amount of air for given amount of fuel is impeded and greatly reduced, and the air-fuel mixture is overly rich for satisfactory engine operation. Frequent adjustments of the carburetor are needed to overcome the effect of this deposit buildup, and finally it becomes necessary to replace the carburetor or give it a complete overhaul.

Various additives have been suggested for use in gasoline to cut down on the buildup of carburetor deposits. However, such additives have usually suffered certain disadvantages as to overall effectiveness, and the search has continued for more suitable compositions.

It has now been found that deposits in the carburetors of spark ignition internal combustion engines are substantially reduced by an improved detergent gasoline composition comprising a major proportion of a hydrocarbon base fuel boiling in the gasoline boiling range and from about 0.0001 to 1.5% by weight of branched-chain alkyl amine having from about 9 to 24 carbon atoms in the alkyl group, the nitrogen atom of said amine having at least one additional substituent selected from the class consisting of alkyl groups of 1 to 6 carbons, hydroxyalkyl, aminoalkyl, polyaminoalkyl and hydroxyalkylarninoalkyl groups in which each of the alkyl groups contains from 2 to 6 carbons.

The branched-chain alkyl amines of the gasoline compositions of the invention are characterized by the formula in which one of the branches, R is a straight-chain alkyl group of from 1 to 3 carbon atoms and the other branch, R is a straight-chain alkyl group of -5 to 22 carbon atoms. R is selected from the class consisting of alkyl groups of 1 to 6 carbons and hydroxyalkyl, aminoalkyl, polyaminoalkyl and hydroxyalkylaminoalkyl groups, said alkyl groups containing from 2 to 6 carbons, and R is hydrogen or alkyl groups of 1 to 6 carbons or hydroxyalkyl, aminoalkyl, polyaminoalkyl or hydroxyalkylaminoalkyl groups having from 2 to 6 carbons in each alkyl group. In the case of the tertiary amines where R and R are both substituents of the foregoing classes, they may be either alike or different. The polyaminoalkyl substituent groups have the general formula in which R is an alkylene or cyclic alkylene group of 2 to -6 carbon atoms, R and R are hydrogen or alkyl groups of 2 to 6 carbon atoms and n is a number from 1 to 7.

The amines of the above type may also be described as N-substituted aminoalkanes, for example, N-hydroxyethyI-Z-aminoalkane, N-aminoethyl-3-aminoalkane, N- aminopropyl-Z-aminoa1kane, N-arninoethyl-aminoethyl-4- aminoalkane, N-tetraethylenepentamine-Z-alkane and N- aminoethylpiperazine-3-alkane in which the alkane is straight-chain and contains 9 to 24 carbon atoms.

Although the branched-chain alkyl substituted amine is satisfactorily employed in any amounts sufiicient to impart detergency to the gasoline composition, it is preferred that it be present in the gasoline in amounts from about 00001 to 1.5% by Weight. For present purposes, amounts in the range from about 0.003 to about 0.05% by Weight are most satisfactory from the standpoint of effectiveness and cost.

To facilitate handling, it is customary to formulate the improved detergent additives of this invention as concentrates. Since the additives are unusually stable and possess good solubility characteristics, these concentrates represent a particular embodiment of the invention. In the preparation of the concentrate, the detergent additive is dissolved in a suitable hydrocarbon or alcohol solvent boiling in the range from about to 400 F., preferably an aromatic hydrocarbon solvent such as benzene, toluene, xylene, or higher boiling aromatics or aromatic thinners. Aliphatic alcohols of 3 to '8 carbon atoms, such as isopropanol, isobutylcarbinol, n-butanol and the like, as well as mutually compatible mixtures of such alcohols and hydrocarbon solvents, are also suitable for use with the detergent additive. The amounts of detergent additive in the concentrate are ordinarily at least 10% by weight, and may vary up to about 70% by weight.

In addition to the detergent additive, other fuel additives may be used in the gasoline compositions of the invention. The deposit-reducing benefits are obtained in combination with lead alkyl antiknock agents, such as tetramethyl lead or tetraethyl lead. Such antiknock agents are ordinarily employed in amounts sufficient to enhance the octane number, usually from about 0.5 to 4 ml./gal.

A nonvolatile light mineral lubricating oil, such as petroleum spray oil, is also a suitable additive for the gasoline compositions of the invention. These oils are believed to act as a carrier for dispersed deposits. They are employed in amounts from about 0.05 to 0.5% by volume based on the final gasoline composition.

The branched-chain alkyl substituted amine detergent additive is available from a number of sources. For example, straight-chain olefinic hydrocarbons of the desired chain length may 'be converted by conventional methods to haloalkanes having halogen in the 2-, 3- or 4-positions, and the resulting haloalkanes may then be treated with amine to give the corresponding branchedchain alkyl substituted amine. Suitable amines include the alkyl amines, the hydroxyalkyl amines, the aminoalkyl amines and polyalkylene polyamines as illustrated by monomethyl amine, benzyl amine, diethanol amine, piperidine, ethylene diamine, hexamethylene diamine, piperazine, tetraethylene pentamine and higher polyethylene amines and polyethyleneoxy amines containing as many as 7 and 8 or more ethylene or ethyleneoxy amine units.

In accordance with the present invention, a preferred class of branched-chain alkyl substituted amines and mixtures thereof is obtained by converting cracked wax olefins to the corresponding haloalkanes and then to the corresponding aminoalkanes. The cracked wax olefins contain from about 9 to 24 carbon atoms, and preferably from about 15 to 20 carbon atoms. Mixtures of cracked wax olefins obtained by the thermal cracking of parafiin waxes are particularly suitable. Such mixtures and their preparation are described in various publications, including US. Patent No. 2,172,228 on Process For The Manufacture Of Olefins. The primary, secondary and tertiary amines produced from these olefins have the amino group attached to the branched-chain alkyl at the 2-, 3- or 4- positions to provide a mixture of branched-chain alkyl groups, i.e., secondary alkyl groups.

As an illustration of the preparation of amines in accordance with the invention, a mixture of alkyl bromides is first prepared by hydrobromination of the thermally cracked wax olefin mixture containing from about 15 to 20 carbon atoms per molecule. This gives a mixture of secondary alkyl bromides, i.e., 2-, 3- and 4 bromoalkanes, which is substantially (about 95% by weight) pure 2- bromowith the remainder being 3- and higher. One mole of the alkyl bromides is reacted with about moles of hydroxyethyl ethylenediamine at about 160 C. under autogenous pressure in an autoclave. Reaction time is about hours. Two layers are formed, the top layer containing the reaction product and the bottom layer containing unreacted hydroxyethylenediamine, which is recovered and recycled as desired. The top layer is washed with an aqueous 25% caustic solution and then with water. The yield is 85% N-hydroxyethylaminoethyl-Z- aminoalkane.

In another preparation, 2.5 moles of ethanol amine are heated with 1 mole of 2-chloroalkanes derived from a thermally cracked wax olefin mixture containing 10 to carbon atoms per molecule. The heating is continued for about 20 hours, following which excess ethanol amine is removed by vacuum distillation and recycled as desired. The distillation is continued to a peak temperature of 160 C. in the reaction vessel at a pressure equivalent to 3 mm. Hg. After cooling, aqueous caustic solution is added to the residue and the product is extracted with a hydrocarbon solvent. The product is then washed three times with hot water and dried to give a yield of 80% N-hydroxyethyl-Z-amino C -C alkanes.

The improved gasoline compositions containing the branched-chain alkyl substituted amines in accordance with the invention provide excellent detergent performance compared to gasoline compositions containing other alkyl amines. Such detergent properties are determined by the generally accepted method of appraising the gasoline compositions in the glass throttle body engine test, which has been especially developed to observe and to evaluate deposits in the carburetors of typical gasoline engines.

In the Glass Throttle Body Test, a 6-cylinder Plymouth automobile engine is set up in the laboratory and is provided with a conventional carburetor modified by the replacement of the metal throttle body section by a removable glass throttle body section. This glass throttle body is a section of glass tubing A" thick, of approximately 1%" outside diameter and about 1% long. An automatic cycler or timer, which consists of a constant-speed electric motor and a magnetic clutch, is provided for insuring cyclic operation of the engine with 7.5 min. idle periods followed by five accelerations to 2000 r.p.m. Crankcase fumes are vented to the carburetor air inlet, since these fumes are now known to be responsible for the larger portion of the deposits. The engine is started up, using leaded gasoline containing a conventional amount of tetraethyl lead (1.5 ml./gal.), but no surface-active additives of any kind. It is run for 4 hours with the blowby fumes being drawn in at the air intake. The engine is then stopped, the glass body is removed, and both sides of it are photographed. Thereupon the dirty glass body is again installed on the engine and run for one hour on the same leaded base gasoline compounded with the detergent-action additive. This time the blowby fumes are not piped to the carburetor. After the run is completed, the glass throttle body is again photographed, and the effectiveness of the detergent-containing gasoline (the percentage of cleanup of deposits) is visually estimated.

In these tests, branched-chain alkyl amine mixtures obtained from cracked wax olefins as described above were evaluated in the gasoline composition at a concentration of 0.003% by weight. They were found to give excellent carburetor cleanups as set out in the following table:

The above test results show that the branched-chain alkyl amines are elfective as detergents in typical gasoline compositions in accordance with recognized methods of quality appraisal. Surprisingly, the branched-chain alkyl amines as illustrated by the Z-aminoalkanes are generally more effective than the straight-chain alkyl amines as illustrated by the representative l-aminoalkanes.

In further tests, the oxidative stability of the branchedchain alkyl amines of the invention was determined in comparison to similar straight-chain l-aminoalkanes. The additives were blended into white oil and heated at 230 F. and at 300 F. The oil was inhibited with 4,4'-methylene bis-(2,6-di-t-butylphenol) against oxidation. It was found that after 24 hours at 230 F., the branched-chain alkyl secondary amines obtained from C -C cracked wax olefins as illustrated by N-hydroxyethyl-Z-aminoalkane lost only about 13% of the basic nitrogen, whereas the l-aminoalkane and oleyl amine each lost about 30% of the basic nitrogen under the same conditions. At 300 F., the decomposition occurs at a much faster rate, and in 8 hours about 40% of oleyl amine is decomposed while only about 8% of the branched'chain alkyl secondary amine decomposed by a loss of basic nitrogen.

In the foregoing illustrations of the invention, the effectiveness of amines derived from mixtures of olefins, such as thermally cracked wax olefin fractions, is particularly apparent. The typical C -C olefins which were employed have the following weight composition:

Such a mixture contains about 92% by weight of straightchain a-olefins, 3% a,w-diOlefinS, 3% internal olefins and 2% branched-chain, naphthenic and other hydrocarbons. In the hydrohalogenation of these olefins a catalyst, such as ferric chloride, is conveniently employed to direct the addition such that the halogen atom attaches to nonterminal carbon atoms, thereby providing the branched-chain alkyl structure for the amine final product. The hydrohalogenation is also customarily carried out at temperatures, such as 30 to 40 C., which are not high enough to cause rearrangement of the olefin double bond. The 2-haloalkanes thus obtained are readily converted to amines by conventional procedures as previously indicated. Small amounts (about or less) of 3- and 4-haloalkanes are also present and lead to the corresponding 3- and 4- amines.

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and Without limitation of the invention. It will be apparent to those skilled in the art that numerous modications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

I claim:

1. An improved detergent gasoline composition comprising a major proportion of a hydrocarbon base fuel boiling in the gasoline boiling range, lead alkyl antiknock agent in amount sufficient to enhance the octane number and from about 0.0001 to 1.5 percent by Weight of a branched-chain alkyl amine having the formula:

(R5NR6)11 R7 in which R is selected from the group consisting of alkylene and cyclic alkylene groups of 2 to 6 carbon atoms, R; and R are selected from the group consisting of hydrogen and alkyl groups of 2 to 6 carbon atoms and n is a number from 1 to 7, and R is hydrogen.

2. The composition of claim 1 in which the branchedchain alkyl amine has the branched-chain alkyl portion identified by the formula:

\CII-- R2 derived from thermally cracked wax olefin mixtures having about 15 to 20 carbon atoms per molecule.

3. The composition of claim 1 in which the branchedchain alkyl amine is characterized by having R as an aminoalkyl group containing from 2 to 6 carbon atoms and R; as hydrogen.

4. The composition of claim 1 in which the branchedchain alkyl amine is characterized by having R as a polyaminoalkyl substituent group of the general formula:

in which R is selected from the group consisting of alkylene and cyclic alkylene groups of 2 to 6 carbon atoms, R and R are selected from the group consisting of hydrogen and alkyl groups of 2 to 6 carbon atoms and n is a number from 1 to 7, and R is hydrogen.

5. An improved detergent gasoline concentrate consistingessentially of a hydrocarbon solvent and from about 10 to percent by weight of the branched-chain alkyl amine of the gasoline composition of claim 1.

References Cited UNITED STATES PATENTS 1,787,789 1/1931 Lovell et a1. 4472 1,954,939 4/ 1934 Magness 4480 2,021,088 11/1935 Pevere 4472 2,684,292 7/1954 Caron et a1 4463 DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,388 ,979 June 18 1968 George J. Kautsky It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as' shown below:

Column 2, line 39, "of 3 to 8" should read of about 3 to Column 6, line 20, the formula reading "(R NH -R should read (R NR -R Signed and sealed this 2nd day of December 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER,

Commissioner of Patents Edward M. Fletcher, In.

Attesting Officer 

